The invention relates to a vehicle airbag and more particularly provides a vent assembly for installation on a wall of an airbag to control the flow of airbag.
It is well known to provide an inflatable airbag for restraining a vehicle occupant. The airbag assembly includes a folded bag which is connected to a source of inflation gas. Release of the inflation gas into the airbag causes the airbag to expand rapidly such that a face wall of the airbag is displaced toward contact with the vehicle occupant. It is well known to provide one or more vent openings in the walls of the airbag to vent inflation gas from the interior of the airbag into the occupant compartment of a vehicle. Airbag vents are commonly provided in a base wall portion of the airbag to direct the vented gas away from the vehicle occupant. It is known to employ various flow control devices to control the flow of inflation gas through the vent opening. The present invention provides a new and improved airbag valve assembly for an airbag.
U.S. Pat. No. 5,246,250 teaches an airbag valve assembly having first and second panels of flexible sheet material overlying one another and being permeable to pass gas therethrough. The panels have edge portions joined together to form a housing envelope. A valve flap panel of flexible sheet material is interposed between the first and second panels so that the valve flap panel is supported for movement across the first and second panels. A tether has a first end attached to the valve flap panel and a second end attached to the fabric of the airbag and is operable to actuate the tether and move the valve flap across the first and second gas permeable panels. The valve flap may be impermeable to airbag inflation gas, with the valve being normally open, but closed when the valve flap is moved by the tether across the first and second panels.
U.S. Pat. No. 6,832,778 B2 teaches an airbag comprising: a variable depth inflatable airbag cushion adapted to be selectively inflatable to a first depth or a second depth greater than the first depth. The airbag cushion includes at least one vent opening. A cover element of substantially pliable material is disposed in overlying relation to the vent opening. The cover element includes an aperture normally disposed in substantial alignment with the vent opening and a blocking portion normally disposed within a folded pleat structure disposed outboard of the vent opening. The cover element is operatively connected to the airbag cushion such that upon inflation of the airbag cushion to said first depth the blocking portion and the aperture remain in their normal positions such that upon inflation of the airbag cushion to said second depth the cover element is placed into tension thereby pulling the aperture away from the vent opening while at least partially collapsing the pleat structure such that the blocking portion is moved into alignment over the vent opening so as to decrease venting across the airbag cushion. The cover element is operatively attached to the airbag cushion by at least one elongate tensioning strap extending between the cover element and at least one shape defining tethering element supported at a surface of the airbag cushion.
There is provided in accordance with one aspect of the invention an airbag for restraining a vehicle occupant comprising an inflatable airbag cushion comprising a flexible sheet material that has at least one vent opening therein. A vent cover comprising a flexible sheet material is fixed to an interior surface of the airbag cushion aligned with the vent opening in the airbag cushion to form a pocket. The vent cover has at least one vent opening therein that allows an airbag inflation gas to escape from the airbag cushion. A vent flap comprising a flexible sheet material is disposed at least partially within the pocket and inboard of the vent openings in the airbag cushion and vent cover. The vent flap is fixed to a tether that extends outboard from the vent flap through an opening in the vent cover to a first end of the tether that is attached directly to the airbag cushion outboard of the vent cover in a permanent manner. The tether also extends inboard from the vent flap to a second end of the tether that is fixed in a releasable manner to a device that reacts to a signal to release the second end of the tether when a sensor senses a predetermined parameter during the deployment of the airbag. The vent flap is pulled in an outboard direction by the tether to become interposed between the vent openings in the airbag cushion and the vent cover and prevent the escape of inflation gas from the airbag cushion through the vent openings in the airbag cushion and the vent cover.